Rails HABTM關聯

Question

我有自我參考的habtm 。

class Label < AR::B
   has_and_belongs_to_many :a_label, :class_name => "Label",
            :join_table => "a_labels",
            :foreign_key => "label_id",
            :association_foreign_key => "a_label_id",
            :uniq => true
end

但是當我創建查詢（使用squeel ）時：

Label.select{:title}.where do
        id.in(Label.select{:a_label_id}.joins(:a_labels).where{
            labels.title.in(list)
          })

架構：

 labels:
 id | title | description | created_at

 a_labels
 label_id | a_label_id    

我收到錯誤消息：

ActiveRecord::ConfigurationError:
   Association named 'a_labels' was not found; perhaps you misspelled it? 

我在哪里弄錯了？ 謝謝。

Answer 1

看起來您只需要在關聯名稱中添加一個“ s”即可。 代替“ a_labels”，改為“ a_labels”。

class Label < AR::B
  has_and_belongs_to_many :a_labels, ...
    ...
end